1. Field of the Invention
The present invention relates to a wafer processing method for dividing a wafer into individual devices along a plurality of crossing division lines formed on the front side of the wafer, the individual devices being formed in a plurality of separate regions defined by the division lines.
2. Description of the Related Art
In a semiconductor device fabrication process, a plurality of crossing division lines are formed on the front side of a substantially disk-shaped semiconductor wafer to thereby define a plurality of separate regions where a plurality of devices such as ICs and LSIs are formed. The semiconductor wafer is cut along the division lines to thereby divide the regions where the devices are formed from each other, thus obtaining the individual devices.
Cutting of the semiconductor wafer along the division lines is usually performed by using a cutting apparatus called a dicing saw. This cutting apparatus includes a chuck table for holding a workpiece, cutting means having a cutting blade for cutting the workpiece held on the chuck table, and feeding means for relatively moving the chuck table and the cutting means. By feeding the chuck table holding the workpiece as rotating the cutting blade, the wafer is cut along each division line.
However, when the wafer is cut by the cutting blade of the cutting apparatus mentioned above, chipping is apt to occur in the periphery of each device chip divided from the wafer, causing a reduction in die strength of each device chip. To solve such a problem, there has been proposed a method including the steps of forming a resist film on the back side of a wafer, exposing to light the region of the resist film corresponding to each division line of the wafer, thereby removing this region by development, and then etching the wafer from the resist film side along the division lines as by plasma etching, thereby dividing the wafer along the division lines (see Japanese Patent Laid-Open No. 2006-120834, for example).